Net profit for the October to December quarter was 55.0 billion rupees ($1.0 billion), a turnaround after four quarters of sliding profits. Revenues rose 10 percent from a year earlier, to 963.1 billion rupees ($17.9 billion).

"RIL's performance has improved in this quarter with margin expansion in petrochemicals and record earnings in the refining business," chairman Mukesh Ambani said in a statement. He pledged to invest over a trillion rupees ($18.6 billion) to upgrade the company's petrochemical and refining businesses, which he said would "secure a significant change in RIL's earning capacity."

Growth of 12 percent in RIL's petrochemicals business, which accounts for nearly a quarter of sales, made up for a 32 percent slump in oil and gas revenue due to weak production.

Gross refining margins rose to $9.6 a barrel during the quarter, the highest since April, beating an expected slide to $8.7 a barrel.